Nutritional efficacy of preterm formula with a partially hydrolyzed protein source: A randomized pilot study

Background: Decreased nitrogen levels, calcium intestinal absorption rates, and plasma amino acid imbalances were reported for preterm infants who wer e fed partially hydrolyzed preterm formulas. In this pilot study, we evalua ted a new formula with modified nitrogen and calcium sources. Methods: During their second week of life, 16 preterm infants were randomly assigned to one of two groups: 9 were fed the new partially hydrolyzed for mula and 7 were fed a conventional formula. Nutrient balance was performed at the end of the first month of life. Amino acid concentrations and anthro pometric parameters were measured at theoretical term. Results: Birth weight and gestational age (mean +/- SD) were similar in the two groups (28.9 +/- 7.0 weeks and 1183 +/- 242 g vs. 27.7 +/- 1.0 weeks a nd 1139 +/- 162 g). Median nitrogen absorption rates (85% vs, 89%, P = 0.03 ) and biological values (59% vs. 69%; P = 0.13) were lower for infants who were fed the new formula than for those fed the conventional formula. After correction for difference in nitrogen intake, there was no significant dif ference in nitrogen retained between the two groups (P = 0.11). Plasma amin o acid concentrations were also similar in the two groups. Median calcium a bsorption tended to be higher in the new-formula group than in the conventi onal-formula group (54% vs. 45%, P = 0.19). At theoretical term, infants fe d the conventional formula were heavier than infants fed the new formula (3 559 +/- 362 g vs. 3193 +/- 384 g, P = 0.04). Conclusions: Because nitrogen content is 10% higher in hydrolyzed-protein f ormula than in entire-protein formula, appropriate nitrogen retention. plas ma amino acid profile, and mineral use can be achieved with the new partial ly hydrolyzed formula. Further studies with larger groups are needed to eva luate the effect on growth.